This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. This program will design and develop a series of potent and highly selective protein-based topical microbicides. The unifying theme of the program is the use of non-pathogenic mucosal bacteria, lactobacilli, to deliver these proteins to mucosal surfaces within the vagina. The administration of genetically modified vaginal isolates of lactobacilli, expressing protein microbicides, is anticipated to prevent access or entry of HIV into host cells and tissues, thereby reducing infection. The product development projects are supported by central core facilities, including administrative, microbiology, and primate safety study cores. In addition to product safety studies conducted in macaques, optimization of colonization conditions and histological evaluation of Lactobacillus association with the vaginal mucosal will be carried out. Determination of an adequate dosing regimen for the bioengineered Lactobacillus will be essential for determining the safety profile of the microbicides, and will address whether there are any unexpected effects of microbicides produced by lactobacilli on vaginal epithelia. Importantly the three unique product development projects highlighted in this application have already completed key "proof-of-concept" studies that set the stage for advanced research and development activities. Furthermore, all three approaches target conserved functional mechanisms used by HIV to achieve a productive infection of its host. As such, these approaches are less likely to be circumvented by the high mutability of viral proteins, an important property of HIV that has impaired the development of effective preventative vaccines.